English: Pinguinus alfrednewtoni Olson, 1977 - fossil auk leg bone (left humerus) from the Miocene of North Carolina, USA. (collected September 1990)

Birds are small to large, warm-blooded, egg-laying, feathered, bipedal vertebrates capable of powered flight (although some are secondarily flightless). Many scientists characterize birds as dinosaurs, but this is consequence of the physical structure of evolutionary diagrams. Birds aren’t dinosaurs. They’re birds. The logic & rationale that some use to justify statements such as “birds are dinosaurs” is the same logic & rationale that results in saying “vertebrates are echinoderms”. Well, no one says the latter. No one should say the former, either.

However, birds are evolutionarily derived from theropod dinosaurs. Birds first appeared in the Triassic or Jurassic, depending on which avian paleontologist you ask. They inhabit a wide variety of terrestrial and surface marine environments, and exhibit considerable variation in behaviors and diets.

The fossil bird leg bone shown here belonged to Pinguinus alfrednewtoni, an ancient, extinct relative of the great auk, which was a Holocene species.

Classification: Animalia, Chordata, Vertebrata, Aves, Charadriiformes, Alcidae or Panalcidae

Locality: quarry north of Aurora, eastern North Carolina, USA

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See info. on the great auk:

en.wiki.x.io/wiki/Great_auk